The effect of cross-contamination in the sequential interfacial polymerization on the RO performance of polyamide bilayer membranes

International audienceIn this study, hexafluoroalcohol-containing polyamide layer (HFAPA) was prepared on top of a conventional polyamide under-layer (REFPA) via sequential interfacial polymerization (SIP) to improve RO separation behavior, and the performance of the resulting bilayer membrane was thoroughly optimized by investigating the effect of cross-contamination in the SIP process. When several coupons of the polyamide bilayer membrane were prepared by SIP of MPD(aq), TMC(hx) and hexafluoroalcohol-containing diamine (HFAMDA)(aq) in the manner of subsequent membrane dipping, unreacted MPD monomer (mostly captured in the porous PSF support) carried over from the 1st interfacial reaction dissolved and accumulated in the 2nd aqueous solution as verified by UV spectroscopic analysis. The MPD contaminant then participated in the 2nd interfacial reaction, forming copolyamide with HFAMDA monomer onto the REFPA. Depending on the amount of MPD contaminant accumulated in the 2nd aqueous solution, the composition of the resulting co-polyamide in the top-layer varied, causing a significant variation of RO performance; the flux was gradually decreased with the increase of MPD contaminants while the salt rejection slightly increased (from 1st coupon toward 4th coupon). This result indicated that a trace amount of MPD contaminant may be necessary to maximize RO separation behavior. Through in-depth performance evaluation of polyamide bilayer membranes prepared by adding various known-amount of MPD into 2nd HFAMDA solution, and also by applying a frame process (2nd amine solution was applied only top surface of membrane) to eliminate uncontrollable MPD contamination, we have successfully demonstrated consistent RO performance, and identified an optimum material composition to provide superior separation performance. The bilayer membrane prepared by adding 1.2 mol% of MPD to the total amount of HFAMDA in the 2nd aqueous solution showed 99.8% NaCl rejection with the water flux of 45 LMH under the cross-flow filtration performed with 2000 ppm NaCl solution at 400 psi, 25 °C

Preeclampsia is Associated with lower Percentages of Regulatory T Cells in Maternal Blood

Objective: Immunological mechanisms are involved in the pathophysiology of preeclampsia. During pregnancy there is an increase in regulatory T (Treg) cells, which has an important role in regulating tolerance to the immunologically distinct fetus. We hypothesised that percentages of Treg cells are decreased in preeclamptic patients. Methods: Peripheral blood was obtained from 26 healthy pregnant controls and 18 preeclamptic patients. Treg cells were measured using flow-cytometry. Results: Women with pregnancies complicated by preeclampsia had significantly lower percentages of CD4(+)FOXP3(+) Treg cells. Conclusion: We conclude that a deficiency of regulatory T cells may play a role in the pathophysiology of preeclampsia

Likely questionnaire-diagnosed food allergy in 78, 890 adults from the northern Netherlands

Background It is challenging to define likely food allergy (FA) in large populations which limited the number of large studies regarding risk factors for FA. Objective We studied the prevalence and characteristics of self-reported FA (s-rFA) in the large, population-based Dutch Lifelines cohort and identified associated risk factors. Methods Likely food allergic cases (LikelyFA) were classified based on questionnaire reported characteristics consistent with FA. Subjects with atypical characteristics were classified as Indeterminate. We investigated 13 potential risk factors for LikelyFA such as birth mode and living on a farm and addressed health-related quality of life (H-RQOL). Results Of the 78, 890 subjects, 12.1% had s-rFA of which 4.0% and 8.1% were classified as LikelyFA and Indeterminate, respectively. Younger age, female sex, asthma, eczema and nasal allergy increased the risk of LikelyFA (p-value range <1.00*10−250–1.29*10−7). Living in a small city/large village or suburb during childhood was associated with a higher risk of LikelyFA than living on a farm (p-value = 7.81*10−4 and p = 4.84*10−4, respectively). Subjects classified as Indeterminate more often reported depression and burn-out compared to those without FA (p-value = 1.46*10−4 and p = 8.39*10−13, respectively). No association was found with ethnicity, (duration of) breastfeeding, birth mode and reported eating disorder. Mental and physical component scores measuring H-RQOL were lower in both those classified as LikelyFA and Indeterminate compared to those without FA. Conclusion The prevalence of s-rFA among adults is considerable and one-third reports characteristics consistent with LikelyFA. Living on a farm decreased the risk of LikelyFA. The association of poorer H-RQOL as well as depression and burn-out with questionable self-perceived FA is striking and a priority for future study

Modeling Vesicle Traffic Reveals Unexpected Consequences for Cdc42p-Mediated Polarity Establishment

SummaryBackgroundPolarization in yeast has been proposed to involve a positive feedback loop whereby the polarity regulator Cdc42p orients actin cables, which deliver vesicles carrying Cdc42p to the polarization site. Previous mathematical models treating Cdc42p traffic as a membrane-free flux suggested that directed traffic would polarize Cdc42p, but it remained unclear whether Cdc42p would become polarized without the membrane-free simplifying assumption.ResultsWe present mathematical models that explicitly consider stochastic vesicle traffic via exocytosis and endocytosis, providing several new insights. Our findings suggest that endocytic cargo influences the timing of vesicle internalization in yeast. Moreover, our models provide quantitative support for the view that integral membrane cargo proteins would become polarized by directed vesicle traffic given the experimentally determined rates of vesicle traffic and diffusion. However, such traffic cannot effectively polarize the more rapidly diffusing Cdc42p in the model without making additional assumptions that seem implausible and lack experimental support.ConclusionsOur findings suggest that actin-directed vesicle traffic would perturb, rather than reinforce, polarization in yeast

Multicentre Double-Blind Placebo-Controlled Food Challenge Study in Children Sensitised to Cashew Nut

Few studies with a limited number of patients have provided indications that cashew-allergic patients may experience severe allergic reactions to minimal amounts of cashew nut. The objectives of this multicentre study were to assess the clinical relevance of cashew nut sensitisation, to study the clinical reaction patterns in double-blind placebo-controlled food challenge tests and to establish the amount of cashew nuts that can elicit an allergic reaction.A total of 179 children were included (median age 9.0 years; range 2-17 years) with cashew nut sensitisation and a clinical history of reactions to cashew nuts or unknown exposure. Sensitised children who could tolerate cashew nuts were excluded. The study included three clinical visits and a telephone consultation. During the first visit, the medical history was evaluated, physical examinations were conducted, blood samples were drawn and skin prick tests were performed. The children underwent a double-blind placebo-controlled food challenge test with cashew nut during the second and third visits. The study showed that 137 (76.5%) of the sensitised children suspected of allergy to cashew nut had a positive double-blind placebo-controlled food challenge test, with 46% (63) manifesting subjective symptoms to the lowest dose of 1 mg cashew nut protein and 11% (15) developing objective symptoms to the lowest dose. Children most frequently had gastro-intestinal symptoms, followed by oral allergy and skin symptoms. A total of 36% (49/137) of the children experienced an anaphylactic reaction and 6% (8/137) of the children were treated with epinephrine.This prospective study demonstrated a strikingly high percentage of clinical reactions to cashew nut in this third line population. Severe allergic reactions, including anaphylaxis requiring epinephrine, were observed. These reactions were to minimal amounts of cashew nut, demonstrated the high potency of this allergens.www.ncbi.nlm.nih.gov/pubmed NTR3572

The feasibility of an allergy management support system (AMSS) for IgE-mediated allergy in primary care

Background: The allergy management support system (AMSS) was developed to assist general practitioners (GPs) to handle the increasing burden of allergic diseases and facilitates the diagnosis and management of allergy. The aim of this cluster-randomized controlled pilot study was to test the feasibility of this AMSS for primary care. Methods: GPs received diagnostic and management recommendations generated by the AMSS in addition to sIgE-test results (intervention) or GPs received sIgE-test results only (control). The AMSS recommendations are based on the previously developed patient-completed AMSS questionnaire and sIgE-test results. The AMSS was considered feasible when > 70% of the AMSS recommendations were sent to the GP within ten working days of sIgE-testing. GPs completed a questionnaire on their diagnosis and management before (T1) and after (T2) receiving sIgE test results. Agreement and disagreement concerning diagnosis, medication and referrals between GPs and AMSS was investigated at T1 and T2. A total agreement score between GPs and AMSS was calculated. GPs in the intervention group completed a questionnaire to evaluate the utility of the AMSS. Semi-structured interviews were used to explore the motivation of GPs who did not include patients in this pilot study. Results: Twenty-seven GPs included 101 patients. Forty-two patients (72%) completed the AMSS questionnaire in the intervention group. The majority of the AMSS recommendations (93%) were returned to the GP within 10 working days after sIgE-test results were known [mean (SD) 4.7 (4.0) working days]. GPs in the intervention group reported largely following the AMSS recommendations in 71% of cases. The total agreement scores concerning diagnosis were significantly higher (p < 0.001) in the intervention group than the control group [mean (SD); 0.9 (1.8) vs - 0.8 (1.0)]. The agreement concerning medication or referral between GPs and AMSS did not differ between the intervention and the control group. GPs in the intervention group were reasonably positive about the AMSS. Not enrolling patients was not caused by anticipated ineffectiveness of the AMSS. Conclusion: The AMSS can be considered to be feasible for primary care. GPs tend to follow the AMSS recommendations. The AMSS may contribute to the empowerment of GPs to better manage allergy patients in primary care.Trial registration ISRCTN ISRCTN36780877. Registered 23 November 2017 (retrospectively registered)

IgE Cross-Reactivity of Cashew Nut Allergens

Background: Allergic sensitisation towards cashew nut often happens without a clear history of eating cashew nut. IgE cross-reactivity between cashew and pistachio nut is well described; however, the ability of cashew nut-specific IgE to cross-react to common tree nut species and other Anacardiaceae, like mango, pink peppercorn, or sumac is largely unknown. Objectives: Cashew nut allergic individuals may cross-react to foods that are phylogenetically related to cashew. We aimed to determine IgE cross-sensitisation and cross-reactivity profiles in cashew nut-sensitised subjects, towards botanically related proteins of other Anacardiaceae family members and related tree nut species. Method: Sera from children with a suspected cashew nut allergy (n = 56) were assessed for IgE sensitisation to common tree nuts, mango, pink peppercorn, and sumac using dot blot technique. Allergen cross-reactivity patterns between Anacardiaceae species were subsequently examined by SDS-PAGE and immunoblot inhibition, and IgE-reactive allergens were identified by LC-MS/MS. Results: From the 56 subjects analysed, 36 were positive on dot blot for cashew nut (63%). Of these, 50% were mono-sensitised to cashew nuts, 19% were co-sensitised to Anacardiaceae species, and 31% were co-sensitised to tree nuts. Subjects co-sensitised to Anacardiaceae species displayed a different allergen recognition pattern than subjects sensitised to common tree nuts. In pink peppercorn, putative albumin- and legumin-type seed storage proteins were found to cross-react with serum of cashew nut-sensitised subjects in vitro. In addition, a putative luminal binding protein was identified, which, among others, may be involved in cross-reactivity between several Anacardiaceae species. Conclusions: Results demonstrate the in vitro presence of IgE cross-sensitisation in children towards multiple Anacardiaceae species. In this study, putative novel allergens were identified in cashew, pistachio, and pink peppercorn, which may pose factors that underlie the observed cross-sensitivity to these species. The clinical relevance of this widespread cross-sensitisation is unknown.</p